在iOS中錄制AVAudioRecorder 256 Kbps

Question

我想在代碼正常的情況下在iOS (AVAudioRecorder)中錄制音頻

_fileName = [NSString stringWithFormat:@"Record_%@.m4a",[DateAndTimeUtil stringFromDate:[NSDate date] withFormatterString:@"HH_mm_ss_dd_MM_yyyy"]];NSArray *pathComponents = [NSArray arrayWithObjects:
                               [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject],
                               _fileName,
                               nil];

NSURL *outputFileURL = [NSURL fileURLWithPathComponents:pathComponents];

// Setup audio session
AVAudioSession *session = [AVAudioSession sharedInstance];
[session setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];

// Define the recorder setting
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];

[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];

// Initiate and prepare the recorder
audioRecorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:nil];
audioRecorder.delegate = self;
audioRecorder.meteringEnabled = YES;
[audioRecorder prepareToRecord];`

問題是錄制的文件顯示的比特率為44 Kbps，但是我想錄制平均比特率為256Kbps的音頻，並且優先選擇AAC編解碼器，而且還與MP3編解碼器和MP4音頻編解碼器兼容。

請幫幫我。

Answer 1

 _fileName = [NSString stringWithFormat:@"Record_%@.mp4",[DateAndTimeUtil stringFromDate:[NSDate date] withFormatterString:@"HH_mm_ss_dd_MM_yyyy"]];
NSArray *pathComponents = [NSArray arrayWithObjects:
                           [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject],
                           _fileName,
                           nil];

NSURL *outputFileURL = [NSURL fileURLWithPathComponents:pathComponents];

// Setup audio session
AVAudioSession *session = [AVAudioSession sharedInstance];
[session setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];

// Define the recorder setting
NSMutableDictionary *recordSetting = [[NSMutableDictionary alloc] init];

[recordSetting setValue:[NSNumber numberWithInt:kAudioFormatMPEG4AAC] forKey:AVFormatIDKey];
[recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];
[recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];
[recordSetting setValue:[NSNumber numberWithInteger:AVAudioQualityHigh] forKey:AVEncoderAudioQualityKey];
[recordSetting setValue:[NSNumber numberWithInt:32] forKey:AVLinearPCMBitDepthKey];
[recordSetting setValue:[NSNumber numberWithInt:128000] forKey:AVEncoderBitRatePerChannelKey];
[recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
[recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];
[recordSetting setValue:[NSNumber numberWithBool:NO] forKey:AVEncoderBitDepthHintKey];


// Initiate and prepare the recorder
audioRecorder = [[AVAudioRecorder alloc] initWithURL:outputFileURL settings:recordSetting error:nil];
audioRecorder.delegate = self;
audioRecorder.meteringEnabled = YES;
[audioRecorder prepareToRecord];

通過使用上面的代碼，我達到了一個積極的解決方案，因為它能夠記錄具有比特率信息的音頻。 音頻的比特率幾乎為256Kbps。